Hydrophobic charge induction

Egisto B, David J, Warren S, Peter T. Hydrophobic charge induction chromatography, Genet Eng News 2000 20. 

Hydrophobic charge induction Mix mode All antibodies Definition of intermediate washings... 

Burton, S. C., and Harding, D. R. (1998). Hydrophobic charge induction chromatography Salt independent protein adsorption and facile elution with aqueous buffers. ]. Chromatogr A 814, 71-81. 

Coulon D, Cabanne C, Fitton V et al. (2004) Penidllin acylase purification with the aid of hydrophobic charge induction chromatography. J Chromat B 808(1) 111-115 Craig RP (1975) The quantitative evaluation of the use of oral proteolytic enzymes in the treatment of sprained ankles. Injury 6(4) 313-316... 

Zhang L, Zhao GF, Sun Y Molecular insight into protein conformational transition in hydrophobic charge induction chromatography a molecular dynamics simulation, J Phys Chem B 113 6873-6880, 2009b. 

The alternatively charging of the encapsuled salty droplet may alternate the repulsion and the attraction between the droplet and the hydrophobic surface that is highly elastic and polarized. This charge induction and the interface interaction might contribute to the tap dance of the droplet. 

Furthermore, the reverse result is observed when the diene is disubstituted at C-8, i.e., 5c, although the mechanistic rationalization of this result is at present unclear. When R1 = OBn 137,138 and OTBDMS139, only poor asymmetric induction is observed. However, when the reaction is carried out in water137,138 or in water-methanol (6 1) I4°, the d.r. rises to 80 20137,13S, and this result is ascribed to some extra charge separation resulting from both secondary orbital interaction and a hydrophobic packing effect of the substrate14,1. 

The electronic properties of amino acid side chains are summarized in Table 3, and they represent a wide spectrum of measures. The NMR data are derived experimentally (37). The dipole (38), C mull, inductive, field, and resonance effects were derived from QM calculations (15). The VHSE5 (39) and Z3 (25) scales were developed for use in quantitative structure-activity relationship analysis of the biologic activity of natural and synthetic peptides. Both were derived from principal components analysis of assorted physico-chemical properties, which included NMR chemical shift data, electron-ion interaction potentials, charges, and isoelectric points. Therefore, these scales are composites rather than primary measures of electronic effects. The validity of these measures is indicated by their lack of overlap with hydrophobicity and steric parameters and by their ability to predict biologic activity of synthetic peptide analogs (25, 39). Finally, coefficients of electrostatic screening by amino acid side chains (ylocal and Ynon-local) were derived from an empirical data set (40), and they represent a composite of electronic effects. 

First, simple inductive effects cannot be used to explain the order of stability of the dialkylthallium(III) derivatives. An increase in the chain length of the alkyl group should reduce the effective charge on the pseudometal ion, and the values of Ki should decrease. Possibly increasing the chain length of R decreases the hydrophobic character of the pseudo-metal ion, and a solvation effect is really reflected by the stability order. A similar effect has been reported previously (20). 

The findings gained with the model system show that two contrary effects characterize the interactions of fluorinated amino acids within the hydrophobic core spatial demand and hydrophobicity on one side, and fluorine-induced polarity on the other. While the increase in hydrophobic surface area upon fluorination may be favorable for hydrophobic interactions, fluorine s inductive effect appears to interfere with the formation of an intact hydrophobic core. In addition, the investigations of fluoroalkyl side-chains in the charged domain as well as the analysis of fluorine s effect on replicase activity indicate that contacts between fluorinated residues may also have an impact on peptide and protein folding. 

Such an expression allows comparison of molecular recognition forces with the interactions encoded in lipophilicity. This is done in Figure 1, where the polar component of lipophilicity is seen to correspond to ion—dipole bonds, hydrogen bonds, orientation forces, and induction forces, whereas the hydrophobic component corresponds to dispersion forces and hydrophobic interactions. Only a limited number of recognition forces cannot find expression in lipophilicity as conventionally measured, namely, ionic bonds, charge transfer interactions, and aryl/aryl stacking interactions. ... 

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